digestive system obtaining nutrients
DESCRIPTION
Energy Body cells need energy to run cell processes. Animals obtain chemical energy from food. Energy is derived from breaking chemical bonds. Food energy is measured in units called calories.TRANSCRIPT
Digestive System Obtaining nutrients Energy Body cells need
energy to run cell processes.
Animals obtain chemical energy fromfood. Energy is derived from
breakingchemical bonds. Food energy is measured in units
calledcalories. Many lipids are made up of fatty acids and
glycerine.
Lipids are fats, oils, andwaxes. Lipids are used forstoring energy,
makingcell membranes, andsynthesizing steroidhormones. No Monomer
Many lipids are made up of fatty acids and glycerine. Starch is
made up of glucose.
Carbohydrates Sugars and starch arethe carbohydrates thathumans can
digest.Fiber is indigestiblecarbohydrates, such ascellulose and
inulin. Glucose is needed byall body cells as energy. Monomer =
monosaccharide Starch is made up of glucose. Proteins are made up
of amino acids.
Amino acids fromdigested proteins areused by cells to build allthe
proteins that ourbody needs. Humans need a balanceof the 20 amino
acids,which can be obtainedfrom animal proteins, orby blending
plantprotein sources. Monomer = amino acids Proteins are made up of
amino acids. Macromolecule summary
Polymers Monomers Roles Complex Carbohydrates (i.e. starch) Glucose
and other simple sugars Broken apart to get energy to make ATP.
Proteins Amino acids Used to make our own enzymes and other body
proteins. Lipids (Fats, waxes, oils, and steroids) None Used for
cellular energy and energy storage; used to make cell membranes,
steroid hormones. Nucleic Acids Nucleotides Store and transmit
hereditary information Digestion Two-way digestion Simple animals
have asingle digestive pouchwith a single opening. Food enters
throughthe opening, wasteleaves through thesame opening. These
organisms mustfinish digesting beforeeating again. One-way
digestion More complex animals have one-way digestion.
Food enters oneopening and wasteleaves from another. Animals with
one-waysystems can eat anytime, which is anadvantage. Mechanical
digestion In humans, mechanicaldigestion takes place in themouth.
Human incisors andcanines are adapted fortearing food, while
molarsare adapted for grindingfood. Saliva, which containsenzymes,
mixes with food. Stomach Acid digestion occurs in the
stomach.
Gastrin, a hormone,stimulates acid release. Pepsin, an enzymethat
breaks upproteins, requires anacidic environment tobecome active.
Duodenum Alkaline digestion takesplace in the upper smallintestine,
the duodenum. Enzymes from thepancreas require analkaline
environment tobe active. Pancreas and Liver Pancreas
releasespancreatic juice,containingbicarbonate, lipases,proteases,
andamylase. The liver makes bile,which emulsifies fats.Bile is made
fromcholesterol, which ismade in the liver. Small intestine The
walls of the smallintestine are lined withmillions of
microvilli.This is the site ofnutrient absorption. Small intestines
alsoproduce manydigestive enzymes tobreak large polymerscompletely
down intomonomers. Digestion and pH Location pH Enzymes Molecules
digested Mouth neutral
Amylase Starch Stomach acidic Pepsin (a peptidase) Initial protein
digestion Small intestine Basic to neutral Mixture of amylase,
peptidases, lipases Digestion of starches, final breakdown of
proteins, digestion of lipids. Large intestine Water from digested
foodis absorbed in the largeintestine. Bacteria present in thelarge
intestine feed onunabsorbed nutrients, andproduce several vitamins.
Fecal material is formedfrom fiber and otherundigested material.
Digestion Diagram Digestion